Why is Newton's law of gravitation called universal law?​

Newtons law of gravitation is called the universal law of gravitation because it is applicable for all masses at all distances, independent of the medium.

Explanation:

For two masses m1 and m2 placed at a distance d, the gravitational force between them will always be given by: Fg=Gd2m1m2. That's why it is a "universal" law.

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.